IME, in a typical zig zaggy trench with less than optimum corner bends
and dirt that insists on getting into your glue, and a myriad of other
defugalties that aren't anticipated while drawing it all out on paper,
it's a miracle if the typical ham ends up with hermetically sealed
joints in the ground, let alone the end terminations.
-Steve K8LX
On 2/27/2013 5:28 PM, Patrick Greenlee wrote:
Jim, I don't disagree with your math but I do disagree with your
statement that you can't seal the conduit. Silicone rubber around snug
fitting holes in a PVC pipe cap are sufficient but if you want to get
super serious you can use compression type bulkhead feed through
fittings, the kind with rubber corks with holes for the wire work very
well. There are others made with O rings that seal good enough to be
used on oceanographic instruments intended to stay water tight at great
depths. My 3 inch buried conduit is dry (I have a pull string and can
swab the bore but have never found water.) The PVC pipe caps can be
installed with an external bead of silicone caulk or Excel rather than
PVC cement. This gives a good seal but can be easily cut with a utility
knife to gain access and reassembled with more caulk.
Patrick AF5ck
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